/*=========================================================================
 *
 *  Copyright UMC Utrecht and contributors
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkCenteredTransformInitializer2.h,v $
  Language:  C++
  Date:      $Date: 2010-07-04 10:30:49 $
  Version:   $Revision: 1.11 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __itkCenteredTransformInitializer2_h
#define __itkCenteredTransformInitializer2_h

#include "itkObject.h"
#include "itkObjectFactory.h"
#include "itkSpatialObject.h"
#include "itkAdvancedImageMomentsCalculator.h"

#include <iostream>

namespace itk
{

/** \class CenteredTransformInitializer2
 * \brief CenteredTransformInitializer2 is a helper class intended to
 * initialize the center of rotation and the translation of Transforms having
 * the center of rotation among their parameters.
 *
 * This class is connected to the fixed image, moving image and transform
 * involved in the registration. Three modes of operation are possible:
 *
 * - Geometrical,
 * - Center of mass,
 * - Origins,
 * - GeometryTop
 *
 * In the first mode, the geometrical center of the fixed image is passed as
 * initial center of rotation to the transform and the vector from the center
 * of the  fixed image to the center of the moving image is passed as the
 * initial translation. This mode basically assumes that the anatomical objects
 * to be registered are centered in their respective images. Hence the best
 * initial guess for the registration is the one that superimposes those two
 * centers.
 *
 * In the second mode, the moments of gray level values are computed
 * for both images. The center of mass of the moving image is then
 * used as center of rotation. The vector between the two centers of
 * mass is passes as the initial translation to the transform. This
 * second approach assumes that the moments of the anatomical objects
 * are similar for both images and hence the best initial guess for
 * registration is to superimpose both mass centers.  Note that this
 * assumption will probably not hold in multi-modality registration.
 *
 * In the third mode, the vector from the coordinates (0,0,0) of the
 * fixed image to the coordinates (0,0,0) of the moving image is passed as the
 * initial translation T and the geometrical center of the
 * moving image, translated by inv(T), is passed as initial center of rotation to the transform.
 *
 * In the fourth mode, the world coordinates of the eight corner points of both
 * images are determined. For both images, the minimum of the elements of world coordinates
 * is taken and the initial translation is taken to be the vector pointing from the minimum
 * coordinates of the fixed image to the minimum coordinates of the moving image. The
 * rotation point is set to the center of the fixed image. Note that this method does not make
 * sense for 2D images, in that case the result will be equal to Geometrical method.
 *
 * \ingroup Transforms
 */
template< class TTransform, class TFixedImage, class TMovingImage >
class CenteredTransformInitializer2 : public Object
{
public:

  /** Standard class typedefs. */
  typedef CenteredTransformInitializer2 Self;
  typedef Object                        Superclass;
  typedef SmartPointer< Self >          Pointer;
  typedef SmartPointer< const Self >    ConstPointer;

  /** New macro for creation of through a Smart Pointer. */
  itkNewMacro( Self );

  /** Run-time type information (and related methods). */
  itkTypeMacro( CenteredTransformInitializer2, Object );

  /** Type of the transform to initialize */
  typedef TTransform                      TransformType;
  typedef typename TransformType::Pointer TransformPointer;

  /** Dimension of parameters. */
  itkStaticConstMacro( InputSpaceDimension, unsigned int,
    TransformType::InputSpaceDimension );
  itkStaticConstMacro( OutputSpaceDimension, unsigned int,
    TransformType::OutputSpaceDimension );

  /** Image Types to use in the initialization of the transform */
  typedef TFixedImage  FixedImageType;
  typedef TMovingImage MovingImageType;

  typedef typename FixedImageType::ConstPointer  FixedImagePointer;
  typedef typename MovingImageType::ConstPointer MovingImagePointer;

  typedef Image< unsigned char, InputSpaceDimension >  FixedImageMaskType;
  typedef Image< unsigned char, OutputSpaceDimension > MovingImageMaskType;
  typedef typename FixedImageMaskType::ConstPointer    FixedImageMaskPointer;
  typedef typename MovingImageMaskType::ConstPointer   MovingImageMaskPointer;

  /** Moment calculators */
  typedef AdvancedImageMomentsCalculator< FixedImageType >
    FixedImageCalculatorType;
  typedef AdvancedImageMomentsCalculator< MovingImageType >
    MovingImageCalculatorType;

  typedef typename FixedImageCalculatorType::Pointer
    FixedImageCalculatorPointer;
  typedef typename MovingImageCalculatorType::Pointer
    MovingImageCalculatorPointer;

  /** Offset type. */
  typedef typename TransformType::OffsetType OffsetType;

  /** Point type. */
  typedef typename TransformType::InputPointType InputPointType;

  /** Vector type. */
  typedef typename TransformType::OutputVectorType OutputVectorType;

  typedef typename FixedImageType::PixelType  InputPixelType;

  /** Set the transform to be initialized */
  itkSetObjectMacro( Transform,   TransformType   );

  /** Set the fixed image used in the registration process */
  itkSetConstObjectMacro( FixedImage,  FixedImageType  );

  /** Set the moving image used in the registration process */
  itkSetConstObjectMacro( MovingImage, MovingImageType );

  /** Mask support. */
  itkSetConstObjectMacro( FixedImageMask, FixedImageMaskType  );
  itkSetConstObjectMacro( MovingImageMask, MovingImageMaskType );

  /** Settings for MomentsCalculator. */
  itkSetMacro( NumberOfSamplesForCenteredTransformInitialization, SizeValueType );
  itkSetMacro( LowerThresholdForCenterGravity, InputPixelType );
  itkSetMacro( CenterOfGravityUsesLowerThreshold, bool );

  /** Initialize the transform using data from the images */
  virtual void InitializeTransform();

  /** Select between using the geometrical center of the images or
      using the center of mass given by the image intensities. */
  void GeometryOn()    { m_UseMoments = false; m_UseOrigins = false; m_UseTop = false; }
  void MomentsOn()     { m_UseMoments = true; m_UseOrigins = false; m_UseTop = false; }
  void OriginsOn()     { m_UseMoments = false; m_UseOrigins = true; m_UseTop = false; }
  void GeometryTopOn() { m_UseMoments = false; m_UseOrigins = false; m_UseTop = true; }

  /** Get() access to the moments calculators */
  itkGetConstObjectMacro( FixedCalculator,  FixedImageCalculatorType  );
  itkGetConstObjectMacro( MovingCalculator, MovingImageCalculatorType );

protected:

  CenteredTransformInitializer2();
  ~CenteredTransformInitializer2() override {}

  void PrintSelf( std::ostream & os, Indent indent ) const override;

  itkGetModifiableObjectMacro( Transform, TransformType );

  /** Settings for MomentsCalculator. */
  SizeValueType  m_NumberOfSamplesForCenteredTransformInitialization;
  InputPixelType m_LowerThresholdForCenterGravity;
  bool           m_CenterOfGravityUsesLowerThreshold;

private:

  CenteredTransformInitializer2( const Self & ); // purposely not implemented
  void operator=( const Self & );                // purposely not implemented

  TransformPointer m_Transform;

  FixedImagePointer      m_FixedImage;
  MovingImagePointer     m_MovingImage;
  FixedImageMaskPointer  m_FixedImageMask;
  MovingImageMaskPointer m_MovingImageMask;

  bool m_UseMoments;
  bool m_UseOrigins;
  bool m_UseTop;

  FixedImageCalculatorPointer  m_FixedCalculator;
  MovingImageCalculatorPointer m_MovingCalculator;

};

}  // namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkCenteredTransformInitializer2.hxx"
#endif

#endif /* __itkCenteredTransformInitializer2_h */
